Subject: about draft-kim-bgp-community-site-multihoming-00

From: Pekka Savola <[email-masked]>
Date: Mon, 27 Oct 2003 21:50:08 +0200 (EET)

Hi,

I had a very brief look at the document 
draft-kim-bgp-community-site-multihoming-00:

        An Application of the BGP Extended Community Attribute for
                     Distributed IPv6 Site Multihoming

.. however, it introduces a number of big problems:

 1) it does not outright spell out which problems it tries to solve, and
it does not really explain why these things are actual problems in RFC
3178 (the site exit routers RFC).  Most of these seem to be confusing,
misguided or wrong to begin with, making it difficult to assess whether 
the mechanism itself is needed or not, or based on the right assumptions.  
These definitely need to be spelled out more.

 2) a new "multihoming community" is introduced which appears to be
totally bogus, trying to replace a BGP route advertisement with an option
which conveys where to forward the packets instead (unless I misunderstood
something)

 3) these models depend on the operation of rest of the internet for 
multihoming.  What incentive would they have to do anything like that?

 4) use of this kind of special community has significant security 
concerns, despite what's described in the memo.  Couldn't anyone hijack 
anyone else's traffic by adding this community to any prefix?

In short, I think the document needs a lot more clarity on what it's
trying to achive and how.  But in the end, I believe (unless I
misunderstood something about the design choices) there will probably be
only little usefulness.

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings

---

From: Iljitsch van Beijnum <[email-masked]>
Date: Tue, 28 Oct 2003 00:15:31 +0100

> draft-kim-bgp-community-site-multihoming-00:

Would it be possible to quote the full URL for drafts? That's much 
easier than having to search for the all over the place.

> .. however, it introduces a number of big problems:

Yes. I don't really understand the whole thing, but it does seem to 
depend on propagating per-multihomed site information throughout the 
network using BGP. If we could do this we wouldn't be here trying to 
come up with all this complicated stuff in the first place. But we 
can't because propagating this information doesn't scale, so we are.

---

From: Pekka Savola <[email-masked]>
Date: Tue, 28 Oct 2003 09:27:58 +0200 (EET)

> easier than having to search for the all over the place.

Unless otherwise stated, prepend them with "www.ietf.org/internet-drafts", 
and you're done :-)

> Yes. I don't really understand the whole thing, 

My perception as wel.. :-)

> but it does seem to 

Exactly..